Year	% of population
1987	35.4
1994	35
1995	33.1
1998	34.8
1999	37.8
2000	40.6
2003	34.8
2004	35
2005	32.9
2006	31.2
2007	30.8
2008	30.4
2009	29.4
2010	28.9
2011	27.9
2012	27.9
2013	27.4
2014	26
2015	26.3
2016	25.9
2017	26.3
2018	26.5
2019	27.2
2020	27.2
2021	27.4
2022	27.5